Back pressure valve



J. L. CURRY BACK PRESSURE VALVE Aug. 19, 1958 3 Sheets-Sheet 2 FiledJune 21. 1956 INVENTOR. F/G- 4- J.L. :URRY

BY Z

A T'TORNEVS Aug. 19, 1958 J. L. CURRY 2,848,053

BACK PRESSURE VALVE l Filed June 21. 1956 5 Sheets-Sheet 3 INVENTOR.

J. L. CURRY F/G. 5. Bm??? United States Patent O BACK PRESSURE VALVEJohn L. Curry, Fort Worth, Tex.,

assigner to Phillips Petroleum Company,

This invention relates to an improved back pressure valve for use in awell conduit such as a casing or tubing string. A specic aspect of theinvention pertains to a combination till collar and ll shoe.

ln the past, in the completion of oil and gas wells, casing stringsoften were run with a float collar and/or a float shoe at or near thebottom of the casing. These devices provided protection against blow outthrough the casing during the running and prevented back flow of thecement, after it was placed behind the casing. However, these deviceshad very serious disadvantages. For example, to prevent collapse of thecasing, due to the weight of the fluid in the annulus, it was necessaryto stop running the casing periodically, so that the pipe could befilled. This resulted in loss of time and, in certain areas, sometimesresulted in stuck casing. Another disadvantage resulted from the factthat, with the back pressure valve installed, a buildup of pressureoccurred immediately below the bottom ofthe casing as it was run intothe well. At times, this pressure buildup was sucient to break down anunderground formation, causing lost circulation and, possibly, blow out.

A prior invention of G. S. Ormsby, disclosed in application Serial No.460,930, filed October 7, 1954, greatly improves the operation in thatit providesV a back pressure valve which is held open during the casingrunning operation, but which is made operable when the casing cementingplug reaches the bottom of the pipe. The present invention is animprovement in that the valve can be made operable at any time while thecasing is being run, before the cementing plug is run, while stillretaining the capacity to be made operable by the casing cementing plug;and it also provides controlling constant ll while running a casing,

One object of the invention is to provide a yback pressure valve for usein a well conduit which leaves the conduit open to llow into its lowerendy during running but which can be released for operation by either acementing plug or an auxiliary actuating device. Another object is toprovide a back pressure valve for use in running a well casing whichleaves the casing open to llow into its lower end but which can bereleased' for operation by either a cementing plug or an .auxiliaryactuating device which can be then moved through the valve to permit owof cement into the annulus surrounding the casing. It is also an objectof the invention to provide a back pressure valve for use in running awell casing which leaves the casing opento flow into its lower end whilebeing run and which has independently operable dual actuating devices,one of which passes on through the valve together with the contactingdevice used in actuating same so as to again open the valve to ilow. Afurther object is to provide a low control check valve in combinationwith the novel back pressure valve of the invention. Other objects ofthe invention will become apparent from a consideration of theaccompanying disclosure.

The present invention comprises a back pressure valve, means to hold thevalve open, a seat for a casing cementing plug, a seat for an auxiliaryactuating device, shear pins which allow the Valve holding means to bemoved into a position which frees the valve for operation, and shearpins which allow the auxiliary actuating device seat to be disengagedafter actuation of the casing cementing plug seat. A more restrictedaspect of the invention comprises the aforesaid structure enclosed in atubular housing or c onduit in combination with an orifice choke checkvalve below same.

A more complete comprehension of the device of the invention may be hadby reference to the accompanying schematic drawings of which Figure l isa partial longitudinal sectional View of the device of the invention;Figure 2 'is a similar view showing the position of the valves duringcirculation; Figure 3 is a similar View showing the valve positions whena cementing plug reaches the actuating member of the upper valve; Figure4 is a similar view showing the valve positions during floating andafter the inner valve seat of the upper valve has been driven throughthe valve seat; and Figure 5 is a similar view showing the valvepositions after knock out and floating with the cementing plug inactuating position. Corresponding elements in the various gures arecorrespondingly numbered.

Referring to Figure l, the numeral 10 designates a cylindrical valvehousing which is provided with internal threads 11 in the upper endportion and external threads 12 on the lower end portion. An annularVvalve support 13 is attached to the inner wall of housing 10 by threads11. Support 13 is provided with a generally circular and tapered valveseat 14 and with vertical holes 15 and 16 which may be two or more innumber. A flapper valve 17 is pivotally attached to support 13 by hinge18 which includes springs 19 and 20 arranged to urge the valve towardand into contact with seat 14. An arcuate or ring member 21 engages alug 22 on the lower edge of valve 17 when in the vertical position tohold valve 17 open. Arcuate member 21 is supported by cylindrical rods23 and 24 and is attached thereto by screws 25 and 26. Rods 23 and 24pass through holes 15 and 16 in slidable engagement with the valvesupport 13 and are held in xed relation therewith by means of shear pins27 and 28. A cementing plug seat 29 is attached to the upper ends ofrods 23 and 24 byy screws 30 and 31. Cementing plug seat 29 is spaced asuicient distance from valve support 13 to permit releasing of valve 17when shear pins 27 and 28 are sheared' by an actuating force applied bya cementing plug or auxiliary actuator pumped into the casing string andinto contact with the actuating mechanism. An auxiliary seat 32 isattached to the inner wall of seat 29 by shear pins 33 and 34 which areof greater strength and require greater shearing force than shear pins27 and 2S. The seating surfaces of seats 29 and 32 are continuous andtake the form of an inverted truncated cone so that an actuatingcontacting device such as a rubber ball or circular plug of smallerdiameter than the internal diameter of seat 29 will actu-ate auxiliaryactuating device 32 and then pass through the axial opening in cementingplug seat 29 and through valve seat opening 14 so as to avoid ob.-structing the downward flow of cement or other fluid through the casingstring. In order for the actuating contactor applied to seat 32 to passthrough the valve device,l

it is essential that the opening in Valve seat 14 and through annularvalve support 13 be at least as large as the actuating contactor. Seats29 and 32 comprise a dual actuating device for releasing valve llapper17.

Housing or collar 10 attached by means of threaded section 12 to acorresponding threaded section of a pipe or casing string 41. On thelower end of the casing section 41 is positioned shoe 42 which isattached to the casing by means of threaded section 43. Threaded intothe upper end of shoe 42 is a valve body 44 into which 1s fitted aspring loaded flapper valve 46 which is urged against the seat by spring47. Flapper valve 46 is provided with an axial orifice 48 whichfunctions as a choke during filling of the pipe or casing string as thecasing 1s run. This orifice is replaceable with any orifice of a sizesmaller than the opening in 32. A bullet-shaped or round nosed element49 is attached to the lower end of shoe 42. Openings 51 in nose 49provide passageways for uids passing into and out of the casing string.

In operation, the housing is attached to the collar of a lower joint ofcasing by threads 12 and to the lower end of an upper joint of casing bythreads 11, thus becoming a part of the casing string. Shoe 42 isattached to the lower end of a joint of casing which connects withcollar v10 or it may be attached to a lower joint of casing in thestring. As the casing is lowered into the well, valve 17 remains in theopen position and the flow of fluid into the lower end of the casingstring is restricted only by the diameter of auxiliary seat 32 or by thediameter of orice 48 when shoe 42 is utilized with fill collar 10. Whenthe casing is in position for cementing, the cement is pumped into thecasing in a normal manner, and the first cementing plug contacts seat29, exerting a force on seat 29, due to the pressure of uid above,forcing seat 29, rods 23 and 24 and ring 21 downward, thereby shearingpins 27 and 28 and releasing valve 17 for operation. However, while thecasing is being run into the well, if it becomes necessary to closevalve 17 to prevent blow out through the casing, an auxiliary actuatingdevice, such as a rubber ball, having an external diameter small enoughto pass through seat 29 but large enough to engage seat 32, is pumpeddownward through the casing. When this device engages seat 32, a forceis applied through shear pins 33 and 34 to seat 29, to rods 23 and 24and ring 21. Since shear pins 33 and 34 are stronger than shear pins 27and 28, shear pins 27 and 28 will be broken, allowing the assembly tomove downward, thus freeing valve 17. When the lower portion of seat 29engages support 13, a further buildup of pressure causes seat 32 and theauxiliary actuating device to move downward, shearing pins 33 and 34 andopening the pipe to circulation in a downward direction.

Flapper valve 46 functions as a partial check valve on fluids flowinginto the casing string when valve 17 is in the position shown in Figurel, the orice 48 acting as a choke and providing controlled constant fillof the casing string when the same is being run into the well containingmud.

Although the device is illustrated in a preferred embodiment comprisinga fiapper back pressure valve, the principle of operation is suitablefor use with other types of back pressure valves, for example, ballcheck valves. The device also can be built into a casing shoe, ifdesired, and run on the bottom of the casing string.

Figure 2 shows the unrestricted passage through the fill collar and shoeduring circulation from the casing string into the annulus of the well.The use of flapper valves insures free passage for the fluid, resultingin greater volumes at reduced pump pressure with higher fluid velocityin the annulus.

The structure shown permits interruption of pipe running to circulatethe well as often and for as long as desired with continued orifice llwhen running of the casing is resumed. The device of the inventiongreatly reduces pressure surges during running of a casing string,thereby decreasing the danger of breaking down weak formations whichresults in lost circulation problems, loss of drilling uids, and dangerof blow outs. It also eliminates time-consuming manual fill, greatlyreduces piperunning time, promotes safety during this operation, andreduces the danger of sticking the casing. It also converts to a floatat any desired point in the operation by dropping a weighted trip ball(shown in Figures 4 and 5) into the casing at the surface so that itgravitates or can be pumped down to the seat 32 in the fill collar,thereby driving this seat through valve body 13 from which it passes onthrough the casing string and through the valve seat in valve body 46coming to a rest in nose 49 where the ball and valve seat do notobstruct ilow through the nose.

Certain modifications of the invention will become apparent to thoseskilled in the art and the illustrative details disclosed are not to beconstrued as imposing unnecessary limitations on the invention.

This application is a continuation-in-part of my copending applicationSerial No. 543,498, led October 28, 1955.

I claim:

1. A back pressure valve for use in a well comprising a tubular housingattachable at the ends to a pipe string; an annular valve supportattached to the inner wall of said housing providing an annular seat foran upwardlyclosing valve closure member; a valve closure memberconforming to said seat and adapted to close the passageway through saidvalve support; a second annular seat supported spaced-apart from theupper side of said valve support; supporting elements for said secondannular seat slidably extending through said valve support and rigidlyattached thereto by shear pins; means on the lower portion of saidsupporting elements for holding said valve closure member away from itsseat when said supporting elements are attached by said shear pins tosaid valve support, and releasing said member when said pins are shearedby a downward force on said second annular seat so as to move samedownwardly; a third annular seat of smaller outer diameter than thediameter of the axial opening in said second annular seat and adapted topass therethrough, said third annular seat being attached to the innerwall of said second annular seat by shear pins requiring greaterdownward shearing force than first said shear pins; and a apper checkvalve, having a flow control orifice therein, positioned in said housingbelow said supporting elements.

2. The valve of claim l wherein said valve closure member comprises aiiapper valve hinged on the lower side of said valve support and springurged into closed position when released.

3. The device of claim 2 wherein said supporting elements comprise atleast two rods extending below said valve support and having extendingtherebetween said holding means comprising an arcuate member at thelevel of the lower edge of said fiapper when fully open and y extendingdownwardly, said arcuate member engaging said edge when said rods areattached to said support by first said shear pins to block its closingand releasing same when rst said shear pins are sheared and said firstannular seat is moved toward said support.

4. The device of claim 1 wherein each said second and third annularseats have the form of a truncated cone and lie in the same conicalsurface so that the inner seat is actuatable independently of the outerseat by a plug of smaller diameter than the inner diameter of said outerseat.

5. A back pressure device for use in a well conduit comprising anupwardly-closing valve; holding and releasing means for said valve; arst actuating means for said releasing means positioned above saidvalve, a second actuating means for said releasing means connectedtherewith and adapted to first actuate said first actuating means underpressure and then, upon additional pressure, to detach from said firstactuating means and pass through said valve so as to avoid obstructingflow therethrough,

said first actuating means being also directly operative.

means by shear pins requiring a larger shearing force than iirst saidshear pins.

7. The device of claim 6 wherein said valve comprises a apper valve,said holding and releasing means is downwardly urged by said firstactuating means upon shearing of first said shear pins by a downwardforce on said rst actuating means, and said first and second actuatingmeans comprise annular coaxial members with said second actuating meansadapted to pass through said first actuating means, each actuating meansbeing provided with an annular seat adapted to receive a generallycircular actuating contactor.

8. A back pressure valve for use in a well comprising a tubular housingattachable at the ends to a pipe string; an annular valve supportattached to the inner wall of said housing providing an annular seat foran upwardly-closing valve closure member; a valve closure memberconforming to said seat and adapted to close the passageway through saidvalve support; a second annular seat supported spaced-apart from theupper side of said Valve support; supporting elements for said secondannular seat slida'bly extending through said valve support and rigidlyattached thereto by shear pins; means on the lower portion of saidsupporting elements for holding said valve closure member away from itsseat when said supporting elements are attached by said shear pins tosaid valve support, and releasing said member when said pins are shearedby a downward force lon said second annular seat so as to move samedownwardly; and a third annular seat of smaller outer diameter than thediameter of the axial opening in said second annular seat and adapted topass therethrough, said third annular seat being attached to the innerwall of said second annular seat by shear pins requiring greaterdownward shearing force than iirst said shear pins.

9. The valve of claim 8 wherein said valve closure member comprises aflapper valve hinged on the lower side of said valve support and springurged into closed position when released.

10. The Valve of claim 9 wherein said supporting elements comprise atleast two rods extending below said valve support and having extendingtherebetween said holding means comprising an arcuate member at thelevel of the lower edge of said apper when fully open and extendingdownwardly, said arcuate member engaging said edge when said rods areattached to said support by tirst said shear pins to block its closingand releasing same when first said shear pins are sheared and said rstannular seat is moved toward said support.

11. The valve of claim 8 wherein each said second and third annularseats have the form of a truncated cone and lie in the same conicalsurface so that the inner seat is actuatable independently on the outerseat by a plug of smaller diameter than the inner diameter of said outerseat.

l2. A back pressure device for use in a well comprising in combinationan annular valve body having means for iixing same in a well casing foraxial fiow through said body; an upwardly-closing valve below said valvebody adapted to seat on said body and prevent upwardly ilow therethru;means for holding said valve ofi its seat; releasing means for saidvalve to permit it to seat; a first actuating means for said releasingmeans comprising an annular member positioned above said valve body; asecond actuating means for said releasing means detachably mounted onsaid first actuating means so that both-move downward as a unit when afirst actuating force is applied to either actuating means, said secondactuating means being separately actuatable thereafter by a secondactuating force of greater magnitude and adapted to pass through. saidvalve body to open said valve after its release by said releasing meansupon actuation of said lirst actuating means.

13'. A back pressure device for use in a well tubing string comprising aconduit adapted to attach to said string; a first upwardly-closing valveand a seat therefor mounted in said conduit; pivotal means supportingsaid valve in said conduit; means for closing said valve when released;iirst releasable holding means for holding said valve away from saidseat and actuatable to release said valve; second releasable holdingmeans for holding said first releasable holding means in iixed relationrelative to said valve seat to hold said valve off said seat; firstreleasing means connected to said iirst releasable holding meansactuatable to release same; second releasing means connected to said rstreleasing means and actuatable to release said iirst releasable holdingmeans when pressure is applied thereto and then, upon greater pressure,to detach from said first releasing means and pass thru said Valve seatso as to avoid obstructing ow therethru, said first releasing meansbeing also operable by direct pressure thereon; a secondupwardly-closing valve in said conduit below said first valve having aflow control orifice therein; and a seat for said second valve mountedin said conduit.

14. The device of claim 13 wherein said second valve moveslongitudinally out of and into engagement with its seat and said owcontrol orifice provides restricted upward ow thru said second valvewhen seated; and said device further includes a partial closure means onthe lower end of said conduit below said second valve having at leastone passageway therethru and a weighted ball in said conduit larger thansaid passageway adapted to actuate said first and second releasingmeans, pass thru said irst and second valve seats, and come to rest onsaid closure means without stopping fluid flow thru said passageway andwithout said ball returning to said orifice upon upward iiuid iiow thrusaid conduit.

l5. A back pressure device for use in a well comprisin combination anannular valve seat positioned across a tubular member adapted to befixed on a tubing string in a well casing for axial fiow thru said seat;an upwardly-closing valve below said valve seat adapted to seat thereonand prevent upward flow therethru; first releasable holding means forholding said valve oi said seat extending upwardly thru said valve seat;pivotal means for supporting said valve; means for closing said valvewhen released; second releasable holding means for holding said iirstreleasable holding means in position holding said valve ofi said seat;first releasing means for releasing said first and second releasableholding means connected with said iirst releasable holding meanscomprising an annular member positioned above said valve seat; secondreleasing means for releasing aforesaid rst and second releasableholding means comprising an annular member detachably mounted on andwithin said first releasing means so that both move downward as a unitwhen a first actuating force is applied to either releasing means, saidsecond releasing means being detachable from said first releasing meansby an actuating force of greater magnitude than said first actuatingforce and adapted to pass thru said valve seat to open said valve after.its release; and a second upwardly closing valve in said tubular memberbelow first said valve having a iiow control orifice therein; and a seatfor said second valve mounted in said tubular member.

16. A back pressure device for use in a well conduit comprising anupwardly-closing valve and a seat therefor; pivotal means supportingsaid valve; means for closing said valve when released; first releasableholding means for holding said valve away from said seat, actuatable torelease said valve; second releasable holding means for holding saidfirst releasable holding means fixed to said valve seat and in positionholding said valve away from said s'eat; irst releasing means connectedto said first releasable holding means actuatable to release said iirstand second releasable holding means and release said valve holding meansfrom said valve; second releasing means connected to said trst releasingmeans and actuatable to release said first and second releasable holdingmeans and pressure is applied thereto and then, upon additionalpressure, to detach from said first releasing means and pass thru saidvalve seat so as to avoid obstructing ow therethru, said first releasingmeans being also operable by direct pressure thereon to release saidfixed valve holding means; and conduit means housing said valve forlongitudinal flow therethru.

17. A back pressure device for use in a well comprising in combinationan annular valve 'seat positioned across a tubular member adapted to befixed on a tubing string in a well casing for axial ow thru said seat;an upwardly-closing valve below said valve seat yadapted to seat thereonand prevent upward ow therethru; first releasable holding means forholding said valve ofi said Vseat extending upwardly thru said valveseat actuatable to release said valve; pivotal means for supporting saidvalve; means for closing said valve when released; second releasableholding means for holding said first releasable holding means fixed tosaid valve seat and in position holding said valve away from said seat;first releasing means for releasing said first and second releasableholding means connected with said first releasable holding meanscomprising an annular member positioned above said valve seat; secondreleasing means for releasing aforesaid first and second releasableholding means comprising an annular member detachably mounted withinsaid first releasing means so that both move downward as a unit when afirst actuating force is applied to either releasing means, said secondreleasing means being detachable from said first releasing means by anactuating force of greater magnitude than said first actuating force andadapted to pass thru said valve seat to open said valve after itsrelease.

18. The device of claim 17 wherein said second releasable holding meanscomprises shear pins extending from said annular valve seat into saidfirst releasable holding means and said second releasing means isattached to said first releasing means by shear pins requiring a largershearing force than first said shear pins.

19. The device of claim 18 wherein said valve comprises a flapper valve,said first releasable holding means is downwardly urged by said firstreleasing means upon shearing of first said shear pins by a downwardforce on said first releasing means, and said first and second releasingmeans comprise annular coaxial members with said second releasing meansbeing adapted to pass thru said first releasing means, each releasingmeans being provided with an annular seat adapted to receive a generallycircular actuating contacter.

References Cited in the file of this patent UNITED STATES PATENTS2,593,520 Baker et al. Apr. 22, 1952 2,735,498 Muse Feb. 21, 19562,751,021 Muse June 19, 1956 2,768,695 Althouse et al. Oct. 30, 1956Patent No. 2,848,053 August 19, 1958 John L. Curry It is herebTcertified that error ap of the above Inumbered patent requiring coPatent should read as corrected below.

pears in the-printed specification 'Y rrection and that the said LettersColumn L6, line 34, for "compris-Y read comprising column r7, line 2,for "and", first occurrence,v read When Signed and sealed this 3rd dayof March 1959.

( SEAL) Attest:

KARL Hf AXLINE ROBERT C. WATSON Attesting Officer Commissioner ofPatents

